Does the LPC1817 have a RNG?

[josvisser]

I know that LPC1817 does not have AES on chip, but does it have a True Random Number Generator?

[josvisser]

Thanks all for solving this out.

Regards,

Jos

[victorjimenez]

Hello Jos,

According to the user manual (UM10430.pdf) page 14 the RNG is only available for the LPC18Sxx parts only. 

Hope it helps! 

Victor.

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[josvisser]

Application note AN11643 describes RNG using the Keil MCB1800/4300 Evaluation Board, which has an LPC1857.

Is this an exception?

I only have an LPCXpresso 18S37 for evaluation, but my target is LPC1817.

[victorjimenez]

Hello Jos, 

You are right, in the application note that you mentioned is using LPC1800/LPC4300. The information regarding the RNG is kind of confusing. I already report this issue. 

To know what information was right if the one in the application note or the one in the datasheet. I modified the example misc_otp_funcs provided in the LPCOpen 2_19 for the LPC4337. I used the evaluation board OM13076 with the LPC4367 to tried this. 

At the end I found out that the application note is right, the LPC4300/LPC1800 does have a RNG. Please see image attach to see the results of the program I made to test this. I ran the example three times to be sure that I was getting different random values each time.

Hope it helps! 

Victor.

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[jamestasker]

Hi Victor,

Would it be possible for you to post the code snippet you used to call the genRand() function and then read that random number?  I'm trying to use the otp_genRand function to produce an IV, but I cannot seem to read it out properly.  Thanks in advance.

[bernhardfink]

If I remember correctly, on low level the RNG is quite easy to handle. I attached a project from the past, but I need to admit that I didn't test it before attaching it.

Regards,

Bernhard.